1. BakerR.H. andBannisterL.H.: ‘Electric power converter’. U.S. Patent 3 867 643 February 1975
2. A New Neutral-Point-Clamped PWM Inverter
3. BakerR.H.: ‘Bridge converter circuit’. U.S. Patent 4 270 163 May 1981
4. HammondP.W.: ‘Medium voltage PWM drive and method’. U.S. Patent 5 625 545 April 1977
5. PengF.Z. andLaiJ.S.: ‘Multilevel cascade voltage‐source inverter with separate DC source’. U.S. Patent 5 642 275 24 June 1997